Cancer is the second-leading cause of death in the U.S. In 2011, the American Cancer Society projects 1,596,670 new cancer cases and 571,950 deaths from cancer. Ovarian cancer is the ninth most common cancer in women and the fifth most common cause of cancer death in women in the U.S. Ovarian cancer includes those tumors that arise from various tissue types of the ovary. Tumors are classified according to the cell type from which they originate, including three main types of tumors: epithelial tumors (including the most common serous subtype), germ cell tumors, and stromal cell tumors. Ovarian cancer is difficult to diagnose at an early stage due to its non-specific symptoms and rapid rate of metastasis. The majority of ovarian cancer cases are therefore diagnosed at a late stage, leading to low survival rates. There is a high unmet need for better methods of detecting and treating ovarian cancer, as well as lung, bladder, thyroid, and other tumor types.